Vulnerability Details CVE-2025-39717
In the Linux kernel, the following vulnerability has been resolved:
open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE
As described in commit 7a54947e727b ('Merge patch series "fs: allow
changing idmappings"'), open_tree_attr(2) was necessary in order to
allow for a detached mount to be created and have its idmappings changed
without the risk of any racing threads operating on it. For this reason,
mount_setattr(2) still does not allow for id-mappings to be changed.
However, there was a bug in commit 2462651ffa76 ("fs: allow changing
idmappings") which allowed users to bypass this restriction by calling
open_tree_attr(2) *without* OPEN_TREE_CLONE.
can_idmap_mount() prevented this bug from allowing an attached
mountpoint's id-mapping from being modified (thanks to an is_anon_ns()
check), but this still allows for detached (but visible) mounts to have
their be id-mapping changed. This risks the same UAF and locking issues
as described in the merge commit, and was likely unintentional.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 6.7%
CVSS Severity
CVSS v3 Score 7.8
Products affected by CVE-2025-39717
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cpe:2.3:o:linux:linux_kernel:6.15
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cpe:2.3:o:linux:linux_kernel:6.15.1
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cpe:2.3:o:linux:linux_kernel:6.15.10
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cpe:2.3:o:linux:linux_kernel:6.15.11
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cpe:2.3:o:linux:linux_kernel:6.15.2
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cpe:2.3:o:linux:linux_kernel:6.15.3
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cpe:2.3:o:linux:linux_kernel:6.15.4
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cpe:2.3:o:linux:linux_kernel:6.15.5
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cpe:2.3:o:linux:linux_kernel:6.15.6
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cpe:2.3:o:linux:linux_kernel:6.15.7
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cpe:2.3:o:linux:linux_kernel:6.15.8
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cpe:2.3:o:linux:linux_kernel:6.15.9
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cpe:2.3:o:linux:linux_kernel:6.16
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cpe:2.3:o:linux:linux_kernel:6.16.1
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cpe:2.3:o:linux:linux_kernel:6.16.2
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cpe:2.3:o:linux:linux_kernel:6.16.3
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cpe:2.3:o:linux:linux_kernel:6.17